The carbohydrate structure of the Con-A unbound fraction of human fibronectin will be investigated from plasma and placental fibronectin preparations. Effort will be directed at elucidating the structural qualities of these preparations which mitigate the binding of the glycopeptides to concanavalin-A Sepharose, since there does not seem to be enough branched mannose in the preparations to account for the behavior. The tissue fibronectin has a much greater proportion of carbohydrate in the con-A unbound fraction. An investigation of the distribution of the carbohydrate on both types of fibronectin will be performed. We will perform additional experiments on human trophoblast cells to investigate the molecular basis of the immune barrier. An investigation of the distribution of glycoproteins and glycopeptides on these cells will be performed using labelled sugars as metabolic precursors in tissue culture. If time permits, an attempt will be made to identify the component(s) removed by trypsin from the trophoblast surface which allow attack by maternal mixed lymphocytes. Additional work performed under support of this grant will be in examination of chemical ionization negative and positive ion mass spectrometry of sachharide derivatives to enhance quantitative methodology.